Adding Custom Dimension to Request Telemetry - Azure functions - azure

Question

I am creating a new Function app using v2.x and I am integrating Application Insights for request logging that is automatically being done as Azure Function is now integrated with App Insights (as mentioned in the documentation link). What I would need to do is log few custom fields in the custom dimensions in Application Insights Request Telemetry. Is it possible without using Custom Request logging (using TrackRequest method)

Answer 1

About adding custom properties, you could refer to this tutorial:Add properties: ITelemetryInitializer. The below is my test a HTTP trigger function.
public static class Function1
{
private static string key = "Your InstrumentationKey";
private static TelemetryClient telemetry = new TelemetryClient() { InstrumentationKey = key };
[FunctionName("Function1")]
public static async Task<IActionResult> Run(
[HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
ILogger log)
{
log.LogInformation("C# HTTP trigger function processed a request.");
if (!telemetry.Context.Properties.ContainsKey("Function_appName"))
{
telemetry.Context.Properties.Add("Function_appName", "testfunc");
}
else
{
telemetry.Context.Properties["Function_appName"] = "testfunc";
}
telemetry.TrackEvent("eventtest");
telemetry.TrackTrace("tracetest");
string name = req.Query["name"];
string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
dynamic data = JsonConvert.DeserializeObject(requestBody);
name = name ?? data?.name;
return name != null
? (ActionResult)new OkObjectResult($"Hello, {name}")
: new BadRequestObjectResult("Please pass a name on the query string or in the request body");
}
}
After running this function, go to the Application Insights Search could check the data Or go to Logs(Analytics).
Update:

Answer 2

You should use ITelemetry Initializer(which can add custom dimension to a specified telemetry like only for request) in function app, please follow the steps below:
1.In Visual studio, create a function app(In my test, I create a blob triggerd function), and install the following nuget packages:
Microsoft.ApplicationInsights, version 2.10.0
Microsoft.NET.Sdk.Functions, version 1.0.29
2.Then in the Function1.cs, write code like below:
using Microsoft.ApplicationInsights.Channel;
using Microsoft.ApplicationInsights.DataContracts;
using Microsoft.ApplicationInsights.Extensibility;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Hosting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using System.IO;
[assembly: WebJobsStartup(typeof(FunctionApp21.MyStartup))]
namespace FunctionApp21
{
public static class Function1
{
[FunctionName("Function1")]
public static void Run([BlobTrigger("samples-workitems/{name}", Connection = "AzureWebJobsStorage")]Stream myBlob, string name, ILogger log)
{
log.LogInformation($"C# Blob trigger function Processed blob\n Name:{name} \n Size: {myBlob.Length} Bytes");
}
}
internal class MyTelemetryInitializer : ITelemetryInitializer
{
public void Initialize(ITelemetry telemetry)
{
//use telemetry is RequestTelemetry to make sure only add to request
if (telemetry != null && telemetry is RequestTelemetry && !telemetry.Context.GlobalProperties.ContainsKey("my_custom_dimen22"))
{
telemetry.Context.GlobalProperties.Add("my_custom_dimen22", "Hello, this is custom dimension for request!!!");
}
}
}
public class MyStartup : IWebJobsStartup
{
public void Configure(IWebJobsBuilder builder)
{
builder.Services.AddSingleton<ITelemetryInitializer, MyTelemetryInitializer>();
}
}
}
3.Publish it to azure, then nav to azure portal -> the published function app -> Monitor -> Add an application insights.
4.Run the function from azure. And wait for a few minutes -> nav to the application insights portal, check the telemetry data, and you can see the custom dimension is only added to request telemetry:

Answer 3

The other solutions don't quite answer the question, how to add custom properties to the request telemetry. There is a very simple solution, add the following within your function's code:
Activity.Current?.AddTag("my_prop", "my_value");
You'll need:
using System.Diagnostics;
This then can be dynamic per function invocation / request, rather a fixed global property.